| 摘要 |
PROBLEM TO BE SOLVED: To detect leading and trailing ends of a document sheet.SOLUTION: In an image reading device 1, leading positions X1, X2 of a document sheet are detected using edge-extraction processing. Also, in the image reading device 1, when the document sheet is read, both of a first CIS light source for reading one face of the document sheet and a second CIS light source for reading the other face of the document sheet are lit regardless of instructions inputted by a user, so that light is received using linear image sensors included in both of the CISs. Thereby, a light receiving amount XB when the document sheet still exists at a reading position of the second CIS and the document no longer exists at a reading position of the first CIS can be made smaller than a light receiving amount Xa when the document sheet does not exist at both of the reading positions. Therefore, even when the light receiving amount XA in reading the document sheet is identical to the light receiving amount Xa when the document sheet does not exist at both of the reading position, a trailing end position Y1 is detected. |
